A beginner's guide to buying a mountain bike

How to recognize a quality bike

You have a limited budget, and you want to get the best bike you
can for the money. If you're not sure what to look for, you could be
mislead by features that seem to make the bike better, but in fact
really don't count for much. Here's what to check out in your bike
search.

The frame

As before, we start with the frame. You should be trying to get
the best frame you can, within reason. There's no need to spend 500
quid on a frame alone, but you definitely shouldn't be contemplating
getting a cheap frame, just so that you can have an (equally cheap)
suspension fork on it.

Most mountain bikes are made of steel or aluminum. There are two
main sorts of steel: high-tensile, and chromoly. High-tensile, aka
hi-ten, is pretty much garbage. Don't buy a bike that has any part
made of hi-ten steel, whether in the main frame or in the fork.
Although there are different sorts of alumimun, there's not much to
distinguish them at this price range.

Nowadays aluminum frames predominate for the price range we are
talking about. This is mainly the result of pressure from the bike
buying public. I have been told by bike shop owners that MTB customers
much prefer alu bikes over steel, and this is why most manufactorers
have abandoned steel for mid-level bikes and above. However alu
doesn't have any clear advantage over steel. It can be made perhaps a
bit lighter, which is an advantage for top end off-road racing bikes,
but is pretty much irrelevant for the midrange bikes we're talking
about here. I think that steel has gotten a bad reputation because of
high-tensile steel. People remember how lousy their first, cheap,
hi-ten bike was, and think that that poor quality is true of all steel
bikes. This is not at all the case, and a few daring manufacturers
(notably Marin) continue to offer high-quality bike frames made from
steel.

For both steel and alu, swaged or butted tubing, which has thinner
walls in the middle (for lightness) and thicker walls at the ends (for
strength) is better than straight-gauge tubing (which is same
thickness throughout).

One thing you should look for on your frame is the ability to
attach things to it. It should have rack/mudguard mounts at the rear
dropouts, and rack mounts on the seat stays. You may think this is not
needed, that you'll never want to use a rack or full mudguards on your
bike, but your needs may change over time. For example, if you get
really into off-road cycling you may decide to buy a full-suspension
bike, and this one will be relegated to riding to work, or for
touring, in which case a rack and mudguards are pretty much
essential.

Another thing that's a good idea to look for, if you think that
it's likely that you'll really get into off-road riding, are disk
brake mounts, both on the main frame and on the fork. These provide
better stopping in the wet and eliminate worn out rims through
braking, and thus are a good upgrade for the serious off-road
rider.

If your frame is aluminum (as most MTBs are nowadays) it should
have a replaceable derailluer hanger. Crashes often knock the
derailluer out of place, and aluminum doesn't tolerate being bent back
into shape (it is likely to break if bent back, while bending back a
derailluer hanger on a steel bike is not a problem).

Suspension fork

If you've decided that you want a suspension fork, you'll want to
know which ones to look for. Generally, sad to say, the more expensive
the forks are, the better they are. The more expensive ones are
stiffer, easier to maintain, and more "plush" (absorbing bumps of all
sizes better). There's quite a variety of fork materials and internal
construction, and it's changing all the time. I haven't kept up
with the changes, having gotten a suspension fork that I really
like! Often MTB magazines run a buyers' guide to forks, so it's best
to get this info from them.

Wheels

While the frame is the heart of the bike, the wheels are what
makes is a bicycle! Most MTB wheels look similar, but when you get
into the details, you'll find the difference between wheels that will
fall apart after one month, vs. ones that will keep spinning happily
until you finally wear out the rims through braking.

Rims. The rim is the outer metal hoop of your wheel. They
are made of aluminum. (At least, all the ones in this price range
should be. For very expensive bikes you can get ones made of carbon
fiber, and for exceedingly cheap bikes they are made out of steel,
which is to be avoided at all costs!) Alu is light and provides a good
surface for brake blocks to bite into, and they shed water quickly
when wet to give you good braking shortly after the brakes pads meet
the metal. In cross section, the rim will usually be something like a
U shape: the tire attaches to the prongs of the U. The bottom part of
the U is often flat on MTB rims, but can be curved, sometimes even
almost pointed, like the bottom of a V. Generally, the more curved or
pointed the inner part of the rim is, the more strength it will have,
but it will also be heavier. One thing that's not so easy to see is
that better rims will have an additional bit of metal across the
bottom of the U. (Rims with this bit of bracing are called box section
if they have a flat part at the bottom of the U, and are called aero
section if the bottom part is more V shaped, and are called open
section if they lack this bracing.) This bracing greatly adds to the
strength of the rim, so much so that it's not a good idea to buy rims
without this extra bracing, even for road use. To find out if the rim
has this extra bracing, you must take the tire off. If the bed of the
rim has wide circular holes in it, then it will be a box or aero
section rim. If instead you can see, underneath the rim tape, small
lumps, these are the heads of the spokes attached directly to the rim,
and it is an open-section rim.

The braking surface of the rim should be plain metal, no colors or
anodizing or anything like that. Colored braking surfaces badly affect
braking. (The exception is for ceramic rims, which do have a coating
on the braking surface, but you won't find these on bikes in this
price range.) Some manufacturers put little grooves in the braking
surface. This improves braking until the edges of the grooves wear
off, but then is the same as for any other rim. I wouldn't pay extra
for it. Colors on rims are fine as long as they aren't on the braking
surface.

Spokes. Generally, MTBs have 32 spokes per wheel. More is
not needed (except for perhaps downhill racing or loading touring
off-road), and fewer makes for a somewhat weaker wheel for not much
weight savings (although some racers do consider this weight savings
significant and get wheels with fewer spokes). Spokes should be
stainless steel. (Some fancy wheel have spokes are made of aluminum or
other materials, but these offer very little benefits over ordinary
steel spokes, and they cost alot more and are much harder to replace
if you break one.) The best spokes are double butted, which means
thinner in the middle than on the end. Butted spokes make for a
lighter but stronger wheel (stronger because they stretch slightly
when subjected to brief but large impacts, thus absorbing the hit,
rather than giving in and buckling the rim). Black spokes are OK, as
long as they are still stainless. The best spoking pattern is the
traditional three-cross, as on the Kona Blast below. You can get
radial spoking on some MTBs, but this is for looks only: it puts much
more strain on the hubs for no benefit.

Kona Blast

The wheel needs to be properly tensioned in order to stay
together. If the spokes are not tight enough, they will rattle loose as you
ride, and then spokes will start to break since the few spokes that
have remained tighter are taking most of the strain. The best way to
check for properly tensioned wheels is to pluck the spokes. For the
front wheel, they should have an even pitch. For the back, the right
side (the side with the gears on it) should have a much higher pitch
than the left side. This is because the right side spokes are shorter
and have a higher tension than the left side spokes. However, the
right side spokes should all have the same tension (hence the same
pitch), and all the left side spokes should have the same pitch, but
it will be lower than the right side, and usually lower than the front
spokes as well.

Hubs. Hubs go around, so the best thing to look for is
good bearings that let them go around with as little resistance as
possible, and good seals to keep them going that way. You can spin the
wheels of a bike you're thinking of buying to see how freely they
spin. One simple test is to attach a spoke wrench to a spoke at the
rim. If the wheels slowly drifts down so that the wrench is at the
bottom, it's got good bearings (note that it may not be completely at
the bottom, as the valve weighs more than other parts of the tube, and
the rim join also weighs more). If the wheel doesn't move at all, it's
not as good, but still may be plenty fine when you're riding it. Ask
your bike shop if you're uncertain about rim quality. As I mentioned
in the previous section (What sort of bike
should you get?), if you think that you may get seriously into
off-road riding, it's worth buying a bike that has disk-ready hubs, so
upgrading to disk brakes will be easier and cheaper.

Tires and tubes. I suppose I ought to say something about
tubeless tires. They are fairly new on the scene, and not many bikes
come with them (certainly none in this price range). I have never used
them, so I can't comment on them from a personal perspective. Right
now, they look to me like something that doesn't have any clear
advantages over the conventional approach, except for racers who are
concerned about every last gram. (For example, if you get a bad puncture
you'll have to put a tube in anyway.) But in a few years time they may
have proven their worth so much that finding a MTB with normal tires
will be as difficult as finding a MTB with rigid forks!

Back to normal tires. They come in a huge variety of tread
patterns, widths, compounds, etc. For on-road use you want a smooth
tire, with width between 1.25" and 2". For off-road use, the choice is
bewildering. Generally, narrower tires are better in the mud (there's
less area for the mud to cling to), but wider tires have more
cushioning and grip. Thus the best tire for you depends on your riding
conditions. Some tires have a Kevlar bead (the bead is the thing on
the very edge of the tire that keeps it on the rim) rather than a
steel one. These reduce the weight of the tire with no drawbacks other
than being a bit more expensive, so are a good idea if you want to
prevent your bike weighing too much.

Tubes are mainly distinguished by the valve type (presta or
schraeder) and width. For width, get them to match your tires. I prefer
presta (aka French valve) to schraeder (aka car tire valve) as I find
them easier to pump up. There's not much to say about tube materials,
other than that I have always gotten along well with plain black
rubber ones of normal thickness.

Components

You should look carefully at the components on the bike. These are
things like brakes, brake levers, shift levers and derailleurs (also
known as gears). Generally, the higher spec components last longer and
are easier to maintain than the lower ones. They are also more
expensive. Getting a good frame should be your priority, but quality
of components can help you choose between bikes that have similar
frames.

The transmition (shift levers and derailleurs) are usually made by
Shimano, so it's useful to know the grades of Shimano components. From
highest to lowest, they are

Shimano Alivio logo

XTR
Deore XT
Deore LX
Deore
Alivio
Acera
Altus
Tourney
You should be looking at getting something at the Alivio range or
better. Often manufacturers mix and match components groups. For
example a bike could come with an Alivio front derailleur and a Deore
rear derailleur. This is sensible, as it puts the better components
where they are most needed and keeps the cost down by putting in
somewhat cheaper components where less is demanded of the part.

Some bikes now come with SRAM transmition components, which are
also good. Generally, the larger the number in the Gripshift
component's name, the better quality the component will be (for
example, 9.0 is better than 7.0). SRAM are best known for their twist
shifters. There are two main varieties of SRAM shifters: the ESP (1:1)
system which requires their own rear derailleur, and 2:1 system, which
works with Shimano rear derailleurs. The Shimano-compatible system
relies on the rear derailleur moving about 2mm for every 1mm of cable
pulled, while the ESP system has the rear derailleur moving about 1mm
for every 1mm of cable. Of these two I much prefer the ESP system, as
I find it too easy to shift more gears than I indended to with the 2:1
system.

Shifters come in two main styles: twist shifters or lever
shifters. It used to be that SRAM made the twist shifters, and Shimano
made the trigger shifters, but now SRAM make some trigger shifters and
vice versa. Most people prefer one or the other, but you won't know
which one you like until you've tried them. Try to test-ride bikes
with both kinds so you'll know which type you'd like to have on your
bike. If you find your dream bike, but it comes with the wrong kind of
shifters, don't despair. The bike shop will often replace them with
the other kind for a small fee or even free.

For brakes and brake levers, Shimano, Dia Compe, Gripshift, and
Avid are brands to look for. Tektro brakes, while not being top-notch,
also do the job pretty well. Never buy a bike with plastic
brakes.

Often bike companies have their own line of parts. For example,
you'll find Specialized components on Specialized bikes and CODA
components on Cannondale bikes. It's sometime hard to tell how good
these parts are. Often they are excellent quality and value
(especially for Specialized and CODA parts), but sometimes they aren't
quite a good quality as you might like. There is no general rule here,
so ask someone you trust about these parts if you're worried about
it.